1. Field of the Invention
This invention pertains to cutting apparatus, particularly fluid jet cutting apparatus that uses a jet of high velocity fluid as a cutting tool, and with still greater particularity, to fluid jet cutting apparatus adapted for motion in at least two dimensions.
2. Description of the Prior Art
Many systems for cutting sheet-like materials have been developed in the past. The most common apparatus used are various types of mechanical saws that operate by moving a series of teeth past the object to be cut. The teeth may be mounted on a disk or band, or strip, and the motion may be continuous, as in a band saw, or reciprocating, as in a saber saw. All saws generate waste chips to the action of the teeth. This waste must be removed to allow action of the saw, particularly when the substance being cut generates inflammable or dangerous waste, such as, graphite fibers or asbestos. The waste problem has led to the introduction of vacuum or fluid flushing systems to remove waste chips or debris. The adoption of composite materials, such as glass or carbon reinforced resins has increased the wear problem on metal cutting teeth, as such materials are harder than most metals. Additionally, many synthetic materials can flow or melt when in contact with the rapidly moving teeth. These, and other problems have led to the development of alternative cutting systems.
The first class of alternative system is that using mechanical means for cutting. Examples include: routers and knives of various types. Systems such as these can lessen, but not eliminate, the problems inherent in saws, as there are still mechanical parts subject to wear, and some generation of chips.
A second type of cutting system is that of using thermal means for cutting. An example is flame cutting torches. Obviously, this method is unsuitable for inflammable materials. Other thermal cutting methods include hot wires and lasers. Hot wires are often used to cut thermoplastics as to generate little waste. Toxic fumes can result, however, and the wires will not penetrate many reinforcing materials, In some industries, high powered lasers have been used to cut materials. The laser has the capability of cutting a wide variety of materials, while producing a narrow kerf with few chips, and little dust. The laser is, however, inefficient in that a large power supply is needed, and the high temperature can lead to production of noxious fumes. For the above reasons, thermal methods cannot be used with many materials.
The third method used for cutting materials, is water jet cutting. In water jet cutting, a source of ultra high pressure water or other fluid is forced through an orifice to form a small diameter stream of high velocity fluid. The pressures used are commonly in the vicinity of 50,000 psi. This high speed jet cuts through most materials, including hard reinforcers, such as carbon fibers or glass. Since the jet is very narrow, only a very small kerf is created, resulting in a very small volume of waste. What waste is created, is removed by fluids in the vicinity of the jet. The result is, almost no dust or chips are created. As the temperature is not elevated, no dangerous fumes are generated. Prior fluid jet systems have been limited to application where a rigid supporting frame can be used due to the necessity of providing a means to take up the reactive force of the jet, and support the supply tubes. Accordingly, conventional water jet cutting apparatus lacks the flexibility found in routers and saws.